1. Field of the Invention
The present invention pertains to a taking lens system, and more particularly to a compact taking lens system that employs a solid-state image pickup element and is suitable for a taking device.
2. Description of the Related Art
In cameras such as video or television cameras that perform taking of an object by receiving, via a solid-state image pickup element in which multiple light receiving elements are arranged in rows, image light rays that exit the taking lens system, a light-converging microlens is mounted on the light entry surface side of the light receiving elements in order to increase their photoreceptive efficiency. To increase (the level of light convergence by this microlens, it is desirable for the light rays that strike the microlens to be parallel to its optical axis. For that purpose, it is necessary for the exit pupil of the taking lens system to be located at or close to infinity, or in other words, for the taking lens system to be essentially telecentric.
On the other hand, it is preferred, from the standpoint of reducing the camera size, to shorten the total length of the taking lens system. However, when the taking lens system is shortened, the exit pupil of said taking lens system becomes close to the image plane. If this happens, the off-axial light rays strike the microlens at an angle. As a result, the degree of light convergence by the microlens is reduced, so that the brightnesses of the central and peripheral areas of the image that is exposed onto the solid-state image pickup element become different.